Note: Descriptions are shown in the official language in which they were submitted.
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9839
20~295~
ICE MACHINE
BACKGROUND OF THE INVENTIOR
The present invention relates to ice making machines
of the type in which an ice mold is refrigerated and water
is recirculated from a water receiver over the refriger-
ated ice mold and back to the water receiver during an ice
making cycle, to freeze ice forms on the ice mold, and the
ice mold is heated and the water recirculation stopped
during an ice harvest cycle, to release the ice forms from
the ice mold. At the start of the ice making cycle, the
ice mold is rapidly cooled by the refrigeration apparatus
10 to a temperature well below freezing and the water is
cooled as it is recirculated over the ice mold. However,
before the ice begins forming a clear ice layer on the ice
mold, ice crystals are likely to start in the recirculat-
ing water and form an ice slush. The time during each ice
15 ~aking cycle at which ice slush begins to be formed
appears to be dependent on various factors including the
refrigerating capacity of the refrigeration apparatus and
hence the rate at which the ice mold i~ cooled; the tem-
perature of the water from the water supply used to qupply
20 an additional quantity of water at the start of each ice
7 making cycle, and the ambient temperature. Different
arrangements have heretofore been proposed for overcoming
the problem of forming ice slush in an ice making machine.
U.S~ Patents 4,550,572 and 4,785,641 disclose recircula-
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2~29S~
tion type ice making machines in which a timing device
delays recirculation of water over the ice mold for a
predetermined time after the start of the ice making
cycle. u.s. Patent 4,715,194 discloses a recirculation
type ice making apparatus in which the water distributing
means is arranged to leave a predetermined dry zone in
which no water is distributed, for the described purpo~e
of causing the dry zone to be somewhat colder than the
remainder of the freezing surface to form an ice nucleuq
for the propagation of ice on the freezing surface.
SUMMARY OF THE INV~NTION
It is an object of the invention to provide a recir-
cularion type ice making machine having an improved
arrangement for preventing formation of ice slush during
an ice making cycle.
Accordingly, the present invention provides an ice
making machine including an ice mold and means for
refrigerating the ice mold during an ice making cycle and
for heating the ice mold during an ice harvest cycle, a
water receiver, and a water inlet valve for controlling
flow of water from a water supply to the water receiver.
The ice machine ha~ a first water control for operating
the water inlet valve to provide an initial quantity of
water in the water receiver prior to the start of each ice
making cycle, and water circulation means including a pump
that iq operable to withdraw water from the receiver and
recirculate water over the ice mold and return unfrozen
water to the receiver during the ice making cycle. A
temperature sensing means senses the temperature of the
water in the receiver and a second water control means is
operative, when the water temperature in the receiver
initially decreases to about water freezing temperature
during an ice making cycle, to open and thereafter close
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the water inlet valve to supply additional water to the
receiver. The total quantity of additional water added
during an ice making cycle is substantially less than the
initial quantity, and the second water control means is
advantageously arranged to open and close the water inlet
valve means only once during the ice making cycle.
The adding of water from the water supply to the
receiver during the ice making cycle, when the temperature
of the water in the receiver initially decrease~ to about
water freezing temperature, prevents the formation of ice
slush and avoids clogging of the water recirculation sys-
tem and degradation of the quality and configuration of
the ice formed in the ice mold.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGURE 1 is a schematic illustration of the refrig-
eration mechanism of an ice making machine embodying the
present invention;
Fig. 2 is a plan view of an ice making machine;
Fig. 3 i9 a schematic electrical diagram of a control
circuit for the ice making machine;
Fig. 3a is schematic electrical diagram of modified
form of water fill control and
Fig. 3b is a schematic diagram of another form of
water fill control.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Figure 1 schematically illustrates an ice making
machine having an ice mold 10 with means for refrigerating
the mold and mean~ circulating water over the ice mold
during an ice making cycle, to freeze ice forms on the
mold, and mean~ for heatin~ the ice mold and stopping
water recirculating during an ice harvest cycle to release
the ice forms from the mold. The refrigeration apparatus
i~ of conventional con~truction and includes a compressor
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12 having a discharge line 13 connected to a condenser 14.
A liquid line 15 from the condenner extends through a
refrigerant expansion control valve 16 to an evaporator 17
disposed in heat exchange relation with the ice mold 10.
S A suction line 18 extend~ from the evaporator 15 back to
the intake of the compreAsor 12. During the ice making
cycle, gaseous refrigerant returning from the evaporator
i~ compres~ed by the compre qor and discharged through
line 13 to the condenser 14 and liquid refrigerant from
the conden~er i~ pa~sed through the expansion valve 16
into the evaporator to refrigerate the mold and freeze ice
forms thereon. The mold i~ heated during the ice harvest
cycle to relea~e the ice form~ from the mold. In the
embodiment illustrated, a normally closed hot gas by-pass
valve 19 in connected between the discharge line 13 of the
compren~or and the evaporator, and the by-pass valve is
operative when open to direct the hot compre~ed ga from
~! the compres~or through the evaporator to heat the ice mold
and free the ice forms from the mold. The compressor
illu~trated is of the air cooled type having a fan 21 that
i4 operable to blow cooling air over the condenser.
A water receiver 11 include~ a ~ump portion lla and a
portion llb that extends below the ice mold 10 to receive
water that drains from the ice mold and convey the water
back to the ~ump. The water recirculation mean~ includes
a pump 25 having an inlet 25a that communicates with the
water receiver and an outlet 25b connected to a pipe 26
leading to a water dintributor 27 arranged to di~tribute
3 water along the upper end of the ice mold for flow down-
i wardly over the ice mold and back to the water receiver.
A water inlet valve 31 in provided for controlling flow of
water from a water ~upply line 32 ~uch a~ a ~ource of tap
water, to the water receiver to provide an initial quan-
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~002954
tity of water in the water receiverO The concentration of
minerals in the water in the water receiver increases a~
the water freezes on the ice mold and selectively operable
means are provided for draining water from the receiver.
In the embodiment illustrated, a discharge valve 35 i~
connected to the water delivery line 26 at a location to
divert water from the pump 25 to a drain line 36.
The water inlet valve 31 is operated to supply an
initial quantity of water in the water recelver prior to
the start of an ice making cycle. During an ice making
cycle, the refrigerating apparatus operates to refrigerate
the ice mold 10 and the recirculation pump 25 is operated
to withdraw water from the receiver and circulate the
water over the ice mold and return unfrozen water from the
ice mold to the receiver. At the start of the ice making
cycle, the ice mold is rapidly cooled by the refrigeration
apparatu~ to a temperature well below freezing and the
water is cooled as it i8 recirculated over the ice mold.
However, before the ice begins forming a clear layer on
the ice mold, ice crystals are likely to start in the
recirculating water and form an ice slu~h. In accordance
with the invention, a temperature sensing means 42 i~
provided for sensing the temperature of the water in the
water receiver, and a water control meanC responsive to
the temperature sensing means is operative during each ice
making cycle when the water temperature receiver initially
decrea~es to about water freezing temperature, for opening
and therea~ter clo~ing the water inlet valve 31 to supply
additional water to the receiver.
A control circuit for operating the ice making
machine is schematically illustrated in Fig. 3. A mode
control 51 is provided for selectively operating the
machine in either an ice making mode or in a wash mode and
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i3 illustrated in Fig. 3 in the ice making mode.
In the following description, it is as~umed that the
water receiver has been filled to a pre~;elected level
either manually or automatically and an upper liquid level
sensor 41 has opened switch 41a, prior to the start of an
ice making cycle. When the mode control 51 is in the ice
making position shown in Fig. 3, switch 51b establi~heq a
circuit to the compre~sor contact relay 52 to energize the
relay and close contactors 52a. Relay contactors 52a,
when closed, establish a circuit to a compressor relay 52b
to start the drive motor 12a for compressor 12. It also
e~tablisheq a circuit through a pre~sure control switch 50
to fan motor 21a to drive the condenser cooling fan 21
under the control of the qwitch 50. When the mode control
51 i~ in the ice making po~ition, the mode select relay Rl
is deenergized and switch 51a applies power from line Ll
through a normally closed bin fill switch 49 to a line
de~ignated Lla in Fig. 3. Line Lla is connected through
the normally closed contacts 53a of a harvest switch 53
and the normally clo~ed contacts Rlb of relay Rl, to a
conductor designated 54 in ~ig 3. Conductor 54 is con-
nected through normally closed contacts R4b of a water
fill relay R4 to the drive motor 25c for water pump 25 to
operate the water pump and circulate water from the water
receiver over the ice mold. When the water pump 25 is
started, the water level in the receiver dropA to a lower
level, due to the water taken up in filling the pipe 26
and distributor 27 and in flowing over the ice mold but
the water fill relay R4 is not re-energized until either
normally relay contacts R2b or R5b are closed.
The temperature sensing means 42 includes a close-on-
drop thermostat 42a and conductor 54 is also connected
through the normally closed contacts R3a of a lockout
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relay R3 and through the normally open contacts of close-
on-drop water thermostat 42a to a water thermo ta~ relay
R5 to energize the water thermostat relay when the tem-
perature in the water receiver drops to substantially
water freezing temperature, namely 0 C. Relay R5, when
energized, close~ normally open relay switch R5a to ener-
gize the lockout relay R3 and lockou~ relay clo~es norm-
ally open relay contacts R3b to maintain relay R3 ener-
gized. Relay R5, when energized, also closes normally
1~ open relay contact~ R5b that are connected in Reries with
a normally cloqed high water level switch 41a operated by
upper liquid level senser 41, to energize a water fill
relay R4. Water fill relay R4, when energized, closes
normally open relay switch R4a to establish a holding
circuit to the water fil~ relay and maintain the water
fill relay energized until the water level again riqeq to
open the high water level switch R41a. Relay R4~ when
energized, al~o closes normally open contacts R4c to ener-
gize water fill solenoid l9a. Thus, the water receiver
2 will be supplied with an additional quantity of water
sufficient to bring the water level back up to the initial
water level, and compen ate for the water required to fill
the water pipe 26 and distributor 27 when the pump was
started at the beginning of the ice making cycle. The
2S lockout relay R3, when energized, closes normally clo~ed
contacts R3b to establi~h a holding circuit and opens
normally clo~ed relay contacts R3a to prevent the water
thermostat from operating the water thermostat relay R5 a
second time when the temperature of the water in the water
receiver again drops to about water freezing temperature
during the ice making cycle. Energization of lockout
relay R3 also closes normally open relay contacts R3c to
maintain the water pump energized, until the lockout relay
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has deactuated in the manner described hereinafter.
After a sufficient ice layer has built up on the ice
mold, the ice making cycle is ~topped and the iC8 har-
vesting is initiated~ In the preferred embodiment dis-
closed, the end of the ice making cycle is sensed by a lowwater switch 58a actuated by a low ~ater level ~ensor 58
arranged to sen~e when the water level in the receiver
drops to a preselected lower level. The low water level
~witch 58a is normally open and i~ connected through a
time delay relay TDa to an end-of-cycle relay R2. Time
delay relay TDa iq a delay-on-make time delay relay which
is operative after power is supplied between terminals 1
and 3, to energize relay R2 connected across terminals 2
and 3, a predetermined time delay after power is applied.
The time delay is adju~table by an adjustable re~istor
connected acro~s terminals 4 and 5, for a preselected
delay interval, for example of the order of 4 seconds.
Low water level 9witch 58a~ when clo~ed, also establishes
a circuit through the normally closed contact~ Rlc of mode
select relay Rl to a discharge valve solenoid 35a to open
the discharge valve 35 ~o that the flow of water from the
pump to the water distributor 27 is stopped and the water
pumped from the receiver is in~tead discharged to drain
36.
A predetermined time interval after closing a low
water level switcn 58a, time delay relay TDa energize~
end-of-cycle relay R2 to close normally open relay con-
tact~ R2a and apply power from line Lla to a conductor
deqignated 61 in Fig. 3. Closing of rélay switch R2a
e~tabli~hes a circuit to the solenoid l9a for the ho~ ga~
valve 19 to open the valve and ~upply hot ga~ to the
evaporator 17 to heat and defrost the same. End-of-cycle
relay R2, when energized, al~o closes normally open con-
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tacts R2b to energize the water fill relay R4 through the
high water level switch 41as to refill the water receiver
unt;l the high water level switch opens.
In the preferred embodiment illustrated, the ice mold
is of the type disclosed in U. S. Patent 4,694~656.
In general~ and as illustrated in Fig. 2, the ice making
mold disclosed in this patent includes a mold structure
having a wall 17a that forms the base of each pocket9 fins
17b that extend outwardly from the wall and form one pair
of opposed sides of each pocket, and movable plates o~
blades 17c that extend transverse to the fins and which
are movable relative to the wall and fins to aid in
ejecting the ice forms from the ;ce mold during the har-
vest cycle. The freezing wall 17a ls preferably cylin-
dr;cal ln form and the fins 17b extend generally horizon-
I tally around the freezing wall while the movable blades
¦ 17c extend generally vertically. A ring 17d engages the
vertical blades 17c and is arranged to mo~e the blades in
different directions in response to movement of the r;ng.
l 20 Vert;cal transfer bars 63 connect the r;ng 17d to a lever
j 64 mounted for pivotal movement about a fixed pivot 65.
Harvest means are operable during the ice harvest cycle to
~ apply a yleldable force to the plates or blades 17c to
31 urge the blades from a f~rst position shown in Fig. 2
¦ 25 toward a second posit;on, to move the ice forms in the
pockets relat;ve to the surface 17a and fins 17b at the
instant the lce blocks are melted free~ and for thereafter
returning the blades from the second back to the first
position. As shown in Fig. 2, a harvest motor 71 is
operative to drive a sha~t 72 through a speed reducing
mechan;sm (not shown). The shaft 72 drives a crank 73 and
a cam 74. A link 75 is pivotally attached to the crank at
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2~295a~
a location spaced from the shaft 72 and a second link 76
is pivotally at~ached to the transfer lever 64. A spring
77 i~ attached to the end~ of the links 75 and 76 and the
qpring i~ guided by relatively telescoping cup~ ~o that
S the spring can transmit both compresqive and tensile
forces between the links 75 and 76. ~he crank and cam are
positioned a~ in Fig. 2 during the ice m~king cycle and
cam 74 has a notch 74a poqitioned to register with the
actuator on the switch 53 to allow the switch53 to move
to a position engaging its normally closed contact 53a as
shown in Fig~ 3. When the cam 74 i~ in the position 3hown
in Fig 2, the crank is arranged to position the lever 64
and hence the movable blades or plates 17c in the po~ition
shown in Fig. 2. A second cam switch 81 is positioned
with its actuator approximately 180 from the actuator of
cam 53 and a harvest switch 82 is positioned so as to be
actuated by the transfer lever 64, when the transfer lever
is moved to its second position. Cam switch 81 iq norm-
ally open but is moved to its closed position by the cam
74 until the cam rotates through one-half revolution to
bring the cam notch 74a into registry with the actuator
for switch 81. Harvest switch 82 is normally open and is
positioned so as to be moved to its closed po~ition when
the lever 64 and blade~ 17c reach their second position.
When the normally open relay contacts R2a are closed,
power is also applied through the cam switch 81 to the
harvest gear motor 71 to drive the cam 74 and lever 73 in
a counterclockwise direction a~ viewed in Fig. 2. The
lever 73 compresses the spring 77, to apply yieldable
force to the lever 64. As the cam 74 rotates, it moves
the switch 53 from a position engaging its normally closed
contact 53a as shown in Fig. 2 to a position enqaging its
normally open contact 53b, to thereby continue energiza-
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tion of the harve~t gear motor when the end-of-cycle relay
R2 is deenergized and open~ contacts R2a. The motor 71
continues rotating the ~haft 72 until the cam notch 74a
regi~ters with the second cam switch 81, to allow the cam
switch 81 to open and s~op the harvest gear motor.
When the hot gas flowing through the evaporator heats
the evaporator sufficient to allow release of the ice
forms from the evaporator and fins, the spring 77 rapidly
moves the lever 64 and blades 17c in a counterclockwise
direction from the firqt position shown in Fig. 2, to a
position in which the lever 64 engages the harvest switch
82 to close the normally open harve3t switch and re-
energize the harve~t gear motor. Shaft 72 is then further
rotated in a counterclockwise direction as viewed in Fig.
2 and cam switch 81 i~ rezlosed by the cam 74 to maintain
a circuit to the harve~t gear motor 90 tha~ the gear motor
continue~ to rotate the shaft until the cam notch 74a
registers with the actuator for the ~witch 53 to allow the
~witch to move from its normally open contact 53b back
into engagement with its normally closed contact 53a. A~
the shaft 72 rotate~ the cam 74 back to its position shown
in Fig. 3, it also moves the transfer arm 64 and blades
70c back to the first position shown in Fig. 2.
Movement of the switch 53 from its normally open
contact back to its normally closed contact, initiates a
succeeding ice making cycle. When the switch 53 moves
away from its normally open contact 53b, it deenergizes
the solenoid l9a to allow the hot gas valve 19 to close
and return the refrigeration apparatus to a condition for
refrigerating the ice mold. Movemen~ of the swi-tch 53 to
it~ normally cloqed contact 53a also energizes the water
pump to ~tart recirculation of water from the water
receiver over the ice mold.
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When the mode control switch 51 is in the wash posi-
tion as shown in Fig. 3, mode relay Rl is energized to
open normally clos0d con~acts Rlb and Rlc and close norm-
ally open contact~ Rla. A manually operable purge switch
91 i~ connected from relay contacts Rla to the water
discharge solenoid 35a to enable selective opening of the
water discharge valve 35. A manually operable switch 92
is also provided to enable selec~ive energization o~ the
water fill solenoid 31a to allow opening of the water fill
valve 31 in the wash mode.
From the foregoing it will be seen that the ice
machine includes a first circuit including end-of-cycle
relay R2, high water level sensor 41, water fill relay R4
and water fill solenoid 31a for operating the water con-
lS trol valve 31 to fill the water receiver to a preselectedupper level, prior to the start of an ice making cycle.
During the ice making cycle, the pump 25 circulates water
from the water receiver through pipe 26 and distributor 27
over the ice mold. The liquid level in the receiver drops
after the pump 25 i~ started and prior to the formation of
ice on the ice mold, because a portion of the water is
taken up in filling pipe 26 and distributor 27 and in
returning over the ice mold to the receiver. When the
temperature in the receiver drops to about water freezing
temperature, a second water control circuit including the
water thermo4tat 42a, water thermostat relay R5, high
level switch R41 and water fill relay R4 are provided to
add water from the water supply to the water receiver
until the water level is again raised up to the ini~ial
high water level, to open switch 41a. Adding water to ~he
water receiver at the time the water temperature initally
drops to water freezing temperature has been found effec-
tive to prevent formation of ice slush in the water recir-
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culation ~ystem. However, it ha~ been found only neces-
sary to add water at the time the water temperature
initially drops to freezing temperature and the lockout
relay R3 is provided to prevent reopening of the water
inlet valve during the remainder of the ice making cycle.
In the preferred embodiment illustrated, the duration of
the ice making cycle is determined by the amount of water
which i~ frozen on the ice mold. The low water temperature
~en~or 58 i~ arranged to clo~e ~witch 58a when the water
level drop~ to a pre3elected level below the high water
level. The amount of water added during the ice making
cycle corresponds generally to only a portion of the water
initially supplied to the receiver, that i~ the portion
taken up in filling up the pipe 26 and di~tribut~ 27 when
lS the pump is qtarted. Since the water thermo~tat relay
refills the receiver after the start of an ice making
cycle and before ice 3tart~ to freeze on the ice mold, the
amount of water in the receiver between the high water
level and the low water level clo~ely reflect~ the amount
of ice built up on ~he ice mold.
A modification in the apparatu~ for controlling addi-
tion of water during the ice making cycle i9 shown in Fi9r
3a. The circuit in Fig~ 3a is adapted to be ~ub~tituted
for the portion of the circuit shown in Fig. 3 below the
points designated X. The circuit of Fig~ 3a i~ the ~ame
a~ the corresponding portion of Fig. 3 except that a
clo~e-on-ri3e thermo~tat 101 i8 provided for sensing when
the water temperature in the receiver ri~e~ to a pre-
~elected temperature, for example 3 or 4 degree~ above
water freezing temperature. The clo3e-on-rise thermo~tat
101 is connected in Rerie3 with normally open relay con-
tact~ R3d of lockout relay R3, and a relay R6. The norm-
ally open contacts R3d of Relay R3 prevent the clo~e on
54
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rise thermo~tat from operating until the lockout relay R3
is energized in response to operation of the close on drop
water thermostat 42a. Relay R6 is operative, when ener-
gized, to open normally closed relay contacts R6a con-
nected in ~erie~ with the water fill relayl to deenergizethe water ill relay when the temperature of the water
ri~es to a pre~elected level above water freezing tempera-
ture .
A further modified circuit for controlling the amoun~
of water added during the ice making cycle is shown in
Fig. 3b. This circuit i~ adapted to be substituted in the
circui~ of Fig. 3 for the portion of the circuit shown
below the points de~ignated X. In the modification shown
in Fig. 3b, a delay on make time delay relay TDb i3 used
to time the addition of water during the ice making cycle.
The time delay relay TDb is connected through normally open
relay contacts R3d of the lockout relay R3 to relay R6.
Relay contacts R3d are closed only when the lockout relay
R3 i~ energized in re~ponse to actuation of the water
thermostat relay R5. Relay TDb is arranged to delay
energization of relay R6 for a predetermined time interval
that i9 correlated at the rate of flow through the water
inlet valve 31, to supply an additional amount of water to
the water receiver during an ice making cycle. Relay R6,
when energized, opens normally closed contacts R6a con-
nected in ~erie8 with the water refill relay, to deener-
gize the water fill relay. The water refill relay will
then remain deenergized for the remainder of the ice
making cycle.
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